The present invention relates to a battery charger, and more particularly to a battery charger capable of charging different size of batteries.
Many products, for example a calculator, a clock, a pager, a Walkman, an electric razor, a flashlight, a camera, etc., are widely used and operated by one or more batteries because they are portable and convenient power source. In order to reduce cost of the batteries and be environmentally friendly, a rechargeable battery is successfully developed. There are many types of commercially available batteries such as Nickel-Cadmium (Nixe2x80x94Cd) batteries, Nickel Metal Hydride batteries, Lead Acid batteries and Lithium Ion batteries.
The standard size of battery usually has been designated as AAA, AA, C, and D. In response to the marketplace""s demand, a battery charger has been developed to simultaneously charge batteries. Such battery charger has a plurality of charging units having predetermined sizes of battery receptacles for receiving specific batteries. For example, if four batteries of size AA or AAA are going to be simultaneously charged, five battery chargers having four charging units (i.e. four AAAs, three AAAs and one AA, two AAAs and two AAs, one AAA and three AAs, and four AAAs) would be manufactured, which is costly and not environmentally friendly. Furthermore, fabricating more battery chargers is necessary when more sizes of batteries and more of different sizes are designed for receiving specific batteries, which is not pleasing to the eye.
A battery charger has been developed to overcome the above drawbacks. FIGS. 1(a) and 1(b) show a typical battery charger capable of charging two standard batteries, e.g. AAA size and AA size, by using springs to expand and contract the length of battery receptacles. The battery charger includes a main body 11 having four sets of charging units, wherein each set of charging unit includes a battery receptacle 12, a contact element 13, an adjusting plate 14 and a slot 15. The adjusting plate 14 is connected to a spring 16 under the battery receptacle 12 and as another contact element. The anode and cathode of a battery to be charged are engaged and electrically connected with the contact element 13 and the adjusting plate 14. In normal condition, the adjusting plate 14 is positioned in one side of the battery receptacle 12 by a pulling force resulted from the spring 16. If the adjusting plate 14 is pulled in the direction distant from the positive electrode contact 13 via the slot 15, the charging unit is capable of charging an AA size battery. Although such charger could simultaneously charge different size batteries, it has the following disadvantages:
(1) The pulling force by the spring 16 needs to be large enough to pull the adjusting plate 14 when an AA size battery is charged, which is inconvenient; and
(2) The elastic fatigue of the spring 15 is common; therefore, the electric engagement of the charging unit could not be achieved.
Therefore, the present invention provides an improved battery charger for overcoming the problems described above.
It is an object of the present invention to provide a battery charger capable of charging a battery selected from one of a first size battery and a second size battery.
It is another object of the present invention to provide a battery charger capable of simultaneously charging different size batteries.
In accordance with one aspect of the present invention, the battery charger includes a housing and at least one charging unit. Each of the charging unit includes a battery receptacle disposed on the housing for receiving and supporting a battery selected from one of a first size battery and a second size battery, a switching device positioned in one side of the battery receptacle and has a metal strip thereon, and a contact element positioned in the other side of the battery receptacle. The first size battery would be charged when the switching device is switched to a first position and the second size battery would be charged when the switching device is switched to a second position.
Preferably, the housing includes an upper housing, a lower housing.
In accordance with another aspect of the present invention, the anode and cathode of the battery are respectively electrically connected with the metal strip and the contact element. Furthermore, the metal strip includes a first protruding pad corresponding to the first size battery and a second protruding pad corresponding to the second size battery. The switching device further includes a protuberance for facilitating adjusting the switching device by hand.
Preferably, the battery receptacle is a concave recess having multiple supporting surfaces.
Preferably, each of the first size battery and the second size battery is selected from a group consisting of size AAA battery, size AA battery, size C battery and size D battery.
The above objects and advantages of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which: